Variations in the Course of the Thenar Motor Branch of the Median Nerve

Hurwitz, Peter Joel

doi:10.1016/s0266-7681(05)80198-6

Cited by 42 publications

(45 citation statements)

References 6 publications

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“…He draw attention to an additional anomaly in seven patients (9%); the motor branch arose from the anterior surface of the median nerve, turning ulnar and crossing the distal edge of the flexor retinaculum under the cover of a hypertrophic abductor pollicis brevis muscle. The nerve can easily be injured during splitting of the flexor retinaculum with this anomaly (14). The nerve should be approached from ulnar side to minimize risk of lesion.…”

Section: Discussionmentioning

confidence: 99%

Anatomic variations of the median nerve in the carpal tunnel: a brief review of the literature

Demirçay¹,

Çivelek²,

Cansever³

et al. 2011

Turkish Neurosurgery

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Carpal tunnel syndrome (CTS) is a common focal peripheral neuropathy. Increased pressure in the carpal tunnel results in median nerve compression and impaired nerve perfusion, leading to discomfort and paresthesia in the affected hand. Surgical division of the transverse carpal ligament is preferred in severe cases of CTS and should be considered when conservative measures fail. A through knowledge of the normal and variant anatomy of the median nerve in the wrist is fundamental in avoiding complications during carpal tunnel release. This paper aims to briefly review the anatomic variations of the median nerve in the carpal tunnel and its implications in carpal tunnel surgery. KeywOrds: Median nerve, Anatomic variation, Carpal tunnel, Transverse carpal ligament ÖZKarpal tünel sendromu (KTS) sık görülen bir periferik nöropatidir. Karpal tünel basıncının artması median sinirin sıkışmasına ve kanlanmasının bozulmasına yol açar. Ağır vakalarda ve konservatif tedavinin yeterli olmadığı durumlarda cerrahi olarak transvers karpal ligamanın kesilmesi tercih edilir. Karpal tünelin gevşetilmesi sırasında komplikasyonlardan kaçınmak için median sinirin bu bölgedeki ayrıntılı anatomisinin ve varyasyonlarının iyi bilinmesi gereklidir. Bu derleme median sinirin karpal tüneldeki olası anatomik varyasyonlarını ve bunun karpal tünel cerrahisine etkilerini kısaca gözden geçirmek amacıyla yazılmıştır.

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Section: Discussionmentioning

confidence: 99%

Anatomic variations of the median nerve in the carpal tunnel: a brief review of the literature

Demirçay¹,

Çivelek²,

Cansever³

et al. 2011

Turkish Neurosurgery

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“…A rare fourth variation has been reported where the motor branch takes off from an ulnar and anterior location, bridging the median nerve as it approaches the thenar musculature ( Figure 3D) (8). Finally, the motor branch may have a course superficial to the transverse carpal ligament, a variation found in 9% of patients undergoing carpal tunnel release surgery ( Figure 3E) (9). Awareness of these variation can prevent injury to the recurrent motor branch.…”

Section: Variations Of the Motor Branch Of The Median Nervementioning

confidence: 99%

Anatomical variations of the carpal tunnel structures

Mitchell¹,

Chesney²,

Seal³

et al. 2009

CAN J PLAST SURG

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Asurgeon's expert competency should include an appreciation of anatomical variations, particularly with respect to common surgical procedures. One such procedure where this is relevant to plastic surgeons is the carpal tunnel release. The carpal tunnel has been recognized as a site where multiple anatomical variations can occur. These variations can involve neural, vascular, tendinous and muscular structures. If these are unrecognized, there is a risk of iatrogenic injury to the involved structures leading to unfavourable surgical outcomes. The purpose of the present review is to highlight recognized anatomical variations within the carpal tunnel and, hopefully, to help practitioners perform safe surgery. The Carpal TunnelThe carpal tunnel is defined as the space deep to the transverse carpal ligament. The transverse carpal ligament extends ulnarly from the hook of hamate and the triquetrum to the scaphoid and the trapezium radially. The carpal tunnel is bordered posteriorly by the carpal bones. Within the carpal tunnel lie the median nerve and nine flexor tendons: the flexor digitorum profundus (FDP) and flexor digitorum superficialis (FDS) tendons to the index, middle, ring and small fingers, as well as the flexor pollicis longus (FPL) tendon. A review of the literature identified variations in the structure within and around the carpal tunnel (Table 1). VariaTion in nerVe anaTomyhigh bifurcation of the median nerve In most subjects, the median nerve courses through the carpal tunnel as a single nerve, dividing to form the digital nerves distal to the transverse carpal ligament. Bifurcation of the median nerve proximal to the transverse carpal ligament is a relatively common anatomical variation present in 1% to 3.3% of individuals undergoing carpal tunnel release surgery (Figure 1) (1-3). High bifurcation of the median nerve can be an isolated finding (7) or it can be associated with a persistent median artery (4) or an accessory muscle belly of the long finger flexor superficialis (1,5,6). A case of a bifid median nerve wherein the radial-sided branch was located in its own compartment within the carpal tunnel has been identified by the senior author (AT) (Figure 2). To our knowledge, this is the first report of this variation. This additional compartment was also released with satisfactory outcome. There are many anatomical variations in and around the carpal tunnel that affect the nerves, tendons and arteries in this area. Awareness of these variations is important both during the clinical examination and during carpal tunnel release. The purpose of the present review is to highlight recognized anatomical variations within the carpal tunnel including variation in nerve anatomy, tendon anatomical variants, vascular anatomical variations and muscle anatomical variations.

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“…As cited in a report by Friedman, 46 the branch originates from the ulnar side of the median nerve in only 1% of instances. A more recent study, 72 which prospectively investigated 80 hands in 61 patients, added that in almost 10% of hands this motor branch precariously travels volar to the FR itself. As it thus lies within hypertrophic preligamentous muscle in these cases, it is especially vulnerable to damage during open dissection or endoscopic incision.…”

Section: Median Nerve Entrapment At the Wristmentioning

confidence: 99%